GO ANIMAL TARASITES AND MESSMATES. 



A curious opinion, quite recently expressed by a 

 naturalist, Mons. Giard, and which is a sign of the times, 

 is that the Peltogaster of the Pagurus has become a 

 Sacculina on the crab ; the host having been transformed, 

 its acolyte has done the same thing under the same 

 influence. 



Professor Semper has also found among the Philip- 

 pine Islands, isopod crustaceans living as messmates 

 after the manner of the peltogasters. Two cirrhipedes 

 of the family of Peltogaster, the Sijlon Ilippolytes and the 

 Sijlon Pandali, have been found by Mons. Sars under the 

 abdomen of the Pandalus hrevirostris. 



There are cirrhipedes on the gasteropod molluscs. 

 The Concholejms Peruviana, that beautiful shell which has 

 long been considered a rarity in our collections, is fre- 

 quented by the Cryptopliiolus ininutus, only a sixth of an 

 inch in length. The Scalpella often inhabit the Sertu- 

 lari^e and other polyps; Oxpiasps, Creusim, Pyrgomae, 

 and Lithotryse inhabit corals. Certain kinds of sponges 

 are regularly invaded by the Acastm of Leach, eight 

 species of which are mentioned by Darwin. As we find 

 elsewhere parasites on parasites, here also we find mess- 

 mates on messmates ; on the common anatifa we per- 

 ceive other genera, and on the Diaderna of the North 

 Pacific, we almost always see Otions and Cineras, The 

 Protolepas hivincta also, a fifth of an inch in length, lives 

 as a messmate in the. mouth of the Alepas cornuta; and 

 the Elminius of Leach also inhabits other cirrhipedes. 

 The Hemioniscus halani, which Goodsir had taken some 

 years ago for the male of the Balanus, is a messmate on 

 these cirrhipedes. Parasites also are found in mess- 

 mates ; the soldier-crab gives lodging to the sexual 



